added potree.py
added potree.py

somehow potree has to be called twice (see potree.py)
for potential error, investigate 404 in network tab
make sure potree/ and PotreeConverter are were expected (i.e. siblings
of code/)
make sure using the fixed branch of PotreeConverter
chromium doesn't seem to work

victorpoughon/master-thesis,victorpoughon/master-thesis